Our Organic Barrier Covers help protect mattresses from dust mites and prevents them from entering and laying their eggs in your bedding. Our barrier cloth is a high thread count SKAL certified organic cotton fabric that is then heat pressed to tighten the fibers to less than a 6 micron opening - recommended to protect against dust mites debris.. We do not contaminate our organic cotton by adding any chemicals or urethanes. This is our fitted sheet style barrier for easier use in conjunction with a full protector for older mattresses or alone.